Why Does Your MTB Chain Keep Dropping Off? | Ask GMBN Tech

– Welcome back to another Ask GMBN Tech This is a weekly tech related mountain bike Q and A session

If you'll ask some questions, get them in those comments below Use the hashtag AskGMBNTech Alternatively, you can email us at the email address at the bottom of the screen right there Don't forget to use that hashtag in the subject heading there, just so we can find your questions, and put them on next week's show So, first up is from Peter Baldry

Hi Doddy, I've recently been getting back into mountain biking, and I've been riding my 2009 Specialized Pitch FSR Comp on the local trails I thought it might be a good idea to upgrade to a SRAM one by 12 groupset Only problem is I have no idea if standards have changed since I used to ride Bottom brackets, hubs, axles, geometry, etc Please help

Also, are there any other key areas that would be worth an upgrade on my bike? Okay, so I just had a quick look at that bike online I can't quite see what backend it's got on it I don't know if it's 142 yet, but there's a chance it could be a 135 Just to clear up, so on the front, you will have 100 mill spacing, and out back you'll either have 135 or 142 mill spacing These days it's a bit more common to see boost, which is 148 on the back, and 110 on the front, so that's a new standard that's available

So next time you upgrade a fork, you might need to upgrade the wheel to go with that You can get spacer adapters, but you do also need to space out the disc by that relevant amount as well, in order for that to be compatible And obviously out back, you won't be able to fit a boost wheel in a 142, because it's simply too wide But again, that's just wheels, so if you're changing your frame, you might have to address that down the line So you can put a one by 12 speed groupset on your bike

No problems at all As far as the cranks up front go, you just need to get a narrow wide compatible chainring There's plenty of options available on the market Of course you could upgrade to a SRAM crankset, and bottom bracket Maybe putting a DUB system in there if you wanted to, which is their new system, but that is compatible across all backwards platforms, so you don't have to worry about that as a compatibility issue

Obviously wheel sizes have changed So you're on 26 Most bikes now are 27 1/2 or 29 inch wheels, so it's another thing to factor in when you do make future upgrades What else? As far as the 12 speed transmission goes, there's a couple of things you need to take into account So, if your bike is eight speed, then I don't think you can

If it's nine speed or upwards, then you can upgrade to it, just simply because the freehub body size is a different size Now there's two different freehub body styles There's the Shimano Classix blind one, and then there's the SRAM XD style So if you wanna use a SRAM one by 12 cassette, really you're gonna need to use the SRAM XD driver body, and it might not be compatible with your hub You do need to special hub for that

However, SRAM do make the NX transmission, which is 12 speed, that does fit onto a Shimano pattern cassette body, which you will probably have on your bike The only downside of this system is the cassette is entirely made from steel, whereas they're only partially steel on the other ones And you lose that 10 tooth smaller sprocket, in favor of having an 11 speed one, which allows the conventional lockring method of mounting it to the bike But it can be done, of course, so you can make all of those And just because your bike's in 2009, I wouldn't worry too much about all this stuff, because you can find ways around all of these issues, and you can just sort of upgrade as you go, so don't worry too much about that

Of course, down the line you're gonna wanna upgrade your bike, so if you upgrade any of those bits and pieces, bear in mind if you're gonna wanna sell them on there, or upgrade them onto your future bike I guess the only other real thing that has changed significantly since 2009 is geometry Your bike I imagine has probably got a stem, probably 70 or 80 millimeters long on it, whereas most bikes now, of an equivalent style bike, you'll be running more like a 30 or 40 millimeter stem So the front of the bikes have got longer, and you have a shorter stem to keep your bars in their same equivalent position, but your front wheel's further out in front of you So this increases your control when descending, it gives you more weight on the front wheel when climbing, so much less of that near wheeling syndrome that you can get on shorter bikes when climbing

Head angles are likely to be a lot slacker than they were on that Pitch, which means more control at speed and on aggressive terrain, and steep terrain So really, bikes have got slightly better, but it's all marginal gains the whole way along The end of the day, your 2009 Specialized Pitch is a fantastic bike, so don't feel like you need to just swap it out Next up is from David Hurst Hi GMBN, I currently have a 2017 Cube Stereo HPA SL

I'm wanting to upgrade my tires, however my wheelset is 584 by 25 internal Will a 26 inch Magic Mary be suitable, and many thanks Yes, provided you've got enough clearance on there, absolutely no problem You'll get a 2

6 on there 25 mill internal is about as narrow as I would possibly say you could get away with a 26 Really I would say a 24 would be a happier fit on that, but the truth is you'll never know until you actually try it

All you might get is a tire with a slightly rounder profile, because bear in mind when you space out the bottom of a tire, you can square up those shoulders, and of course a 26 is an awfully big tire You might be able to try it in the bike shop, just for size on there, just a dry fit to see if it goes on okay, but I think you could do it, yeah Bike comparison time now So this one is from Joel Watkins

I'm saving up for an Orange Crush 2019 model comp hardtail, however, I can't decide on which version For the same cost, I can get either a 27 1/2, with 150 mill travel fork, or a 29er with 140 mill The bike's for enduro, and fast, rough trail riding with roots and drops Which one is better? More travel, or bigger wheels? PS

, I'm six foot one if that has an effect Thanks in advance To be honest mate, just get the 29er Straight out So, you're a tall dude, so you'll make the most of those big wheels

They'll fit you really well You can ignore all that chattery stuff that gets in the way on a hardtail with those bigger wheels Being a 2019 model, you could also make the most of it by getting some bigger volume tires, further increasing on that And yeah, just because it's got 140, you could jack it up to a 150, and that bike will handle it Slacken it out slightly as well

Dude, it will go like a freight train Get involved with the 29ers I promise you, you will love it Okay, a handlebar related question from Gabriel Bofinger I have a little notch on my Race Face Atlas handlebars from something rubbing on it during transit

The big one is just the paint, but a smaller one is about 5 millimeter deep Do you think it's anything I need to worry about? I absolutely love these bars, and would hate to toss them out On the other hand, the thought of my bars breaking during a ride is terrifying I've been riding like this for a couple of months so far, and it does seem to be fine

Greetings from Germany, by the way Well I think the manufacturer, Race Face, will tell you straightaway to not ride those bars You don't need to be genius to work out that any scoring on an aluminum bar could lead to a catastrophic failure Although you say it's only tiny, and 5 mill thick, and I myself have ridden bars with worse scars on them in the past, perhaps on extended riding trips where I've done that during a crash, and continued to ride the bike, however you really should look at getting those bars changed

I hate to say that If you want a second opinion on that, definitely take it to your nearest bike shop and see what they say, although I'm sure that they will want to wash their hands, and say no, you should change those bars to be safe At the end of the day, handlebars are a safety related item Snapping handlebars is one of the worst things that can happen, because you think of all the additional things that could happen Facial injuries

Sternum injuries, if your stem goes into your chest There's a lot of bad things that can happen I hate to say it dude, but maybe it's the time to get those recycled, and get a new pair of bars on your bike Alrighty, next up from Taylor Brooker Hi Doddy, in a few recent rides I've started to notice a creaking sound situated around the headset area

I have cleaned and regreased my headset, hoping to resolve it, but the creak remains It also tends to only occur when I'm riding down the mountain Would really appreciate your help This is one of those process of elimination things Taylor So, you've just said that you cleaned and regreased the headset

Have you disassembled anything else? So, the two things that immediately stand out to me are the crown race, that's what sits on the fork, and the bearing sits effectively onto it, and it goes into the frame Now the crown race generally is something that you need to press onto the bike, so it doesn't normally come lose However, on many modern headsets and modern bikes, you get split crown races, like this one just in the image here Now, a split crown race, they're very easy and convenient to put on, because you don't need specific tools to do so, however, they're just as easy for grit and grime to find their way underneath them, and anything like that, that has that amount of force going through it, the teeniest amount of movement can create the most god awful creaking So, that could be your problem

The other thing is, depending on how thin your cups are, and what your frame material is made of, the cups could be dry, and they could be moving in the frame They only have to move a microscopic amount for creaking to occur So, if you haven't got the suitable tools to take them out, maybe pop around to a friend's house that has You'll need a Rocket tool, in order to remove the cups from the frame, which, hold on, looks like one of those bad boys So basically the idea of these, is you slide them onto the inside of the frame, until that locates just below that top cup, and that will pop out underneath it, and secure itself

Strike it with a mallet, preferably wooden or plastic ended, and the cups will come out the frame Repeat for the bottom cup Now that's the official tool You can do this with a punch, and old, blunt screwdriver you don't plan on using again, but you can damage your frame, and you can damage the cups, so you're on your own, if you wanna do that method Now when you put the cups back in, use some grease onto the frame itself to make sure that they fit in nice and snug

And hopefully that will get rid of the creaking Of course the only other thing it could be is the steerer tube creaking within the crown of the fork So if you've got a suspension fork, the steerer tube itself is press fitted when they're manufactured into there, and you do get occasions of the steerer tube itself creaking slightly within that crown I've had that in the past before It drove me mad, because I tried everything else on the bike to find out what it was, and ended up being that

So, that process of elimination You're gonna have to have a look at those things yourself, but good luck dude Next up is form Andrea Calligaro Hi Doddy, I've got an issue with the clutch of my SRAM X01 rear derailleur with a 21 clutch

I used to run my bike with no chain falls whatsoever, but in the last months it started to fall often, and on big compressions Sometimes I get chainsuck, so the tire goes between the chainstay and the tire Even after replacing the chainring and the chain itself, nothing changed, so I really feel it has to be something to do with the clutch Is there anything I can do to make my clutch stronger, or is the only way to replace the derailleur? Now first up, just check the clutch is working properly, by giving it a push forwards There should be a lot of resistance when you push the derailleur forwards

If there's no resistance, then the clutch might have failed, in which case there could be a chance that your derailleur's under warranty, if it's under a year old If not, you might wanna replace that Another thing it could be is if your chain is a few links too long Even with the clutch working correctly on the derailleur, the chain still will flap a bit, and if it's close to, the chain line's close to the tire, and it catches on that tire, it's gonna pull it in that gap between the chainstay and the tire Another thing you could do is to have a small chain guard

One of those one-by style chain guides There's two different types There's those that just have a basic sort of clasp, that just sits over the chain, just to make sure it stays on track And then there's more secure ones, just like this MRP one onscreen, which resembles the cage of a front derailleur, and it has that bottom bar there That bottom bar's good, because that stops the chain actually having too much of a downward sort of flop, and going in that gap between your tire and the chainstay

So, have a look at those factors there, and also maybe consider looking at a chain guide And next up is from Piotr Skulmowski Hi, I have a SRAM Roam 30 wheeelset, which came with my 2015 Canyon Strive AL 60 I'm constantly facing a problem of spokes getting loose

Even after maintenance, spokes in the rear wheel are getting loose, and are making noise after just one day in the bike park, for example I find these wheels very weak in general, as I mostly ride like an aggressive XC, and after a few weekends of the year at proper rocky mountain like trails, I'm really concerned about them Should I build this wheel up into another rim and spokes? It's hard to find decent enduro rims with 24 holes Well spokes can unwind themselves with time, and especially straight pull spokes, can have this effect One way around this is to get some spoke thread lock

Now just for example, DT make pro lock nipples, and they have a spoke thread lock agent inside them, to prevent exactly this problem So that's definitely something you can consider And also, make sure, when your wheels are retensioned or trued up, they are tensioned correctly, and they're tensioned all the way around Now a great way of doing that is by using a spoke tension meter, like this Park Tools one And, go onto Park Tool's website, and they've got an app with all the readings that you can do on the tension meter

It builds a replica of your real wheel, and it tells you about the tension, and basically what you need to do to make sure the tension is perfect around the whole wheel Now this was something that Calvin showed me through, when he was here recently, and I was blown away by how accurate this is So you can actually make sure your wheel is perfectly tensioned, as well as making sure at the same time you put some spoke thread lock on there, to stop those spokes unwinding themselves, and hopefully your wheelset will be fine However, if you are still struggling with that, then by all means, consider looking at a wider rim, a slightly chunkier option, and you might wanna look at traditional J bend spokes, if you're suffering from this as a problem So there we go

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